Multimodality Brain Imaging Markers in Progressive Supranuclear Palsy Subtypes and Parkinson's Disease

The new classification of progressive supranuclear palsy (PSP) subtypes necessitates identifying radiological biomarkers to support the clinical diagnosis.

The goal was to test if magnetic resonance imaging (MRI) morphometry, diffusion tensor imaging (DTI), susceptibility-weighted imaging (SWI), or [18F]fluorodeoxyglucose (^18FFDG)-positron emission tomography (PET) differentiates PSP subtypes from each other or Parkinson's disease (PD).

Midbrain/pons (M/P) area ratio, middle/superior cerebellar peduncle (MCP/SCP) width ratio, magnetic resonance parkinsonism indices (MRPI and MRPI2) and midbrain antero-posterior (AP) diameter were measured. Region of interest-based DTI, SWI, and ^18FFDG-PET analyses were performed.

Four PSP subtypes (n = 85) and 24 PD were studied. MRI morphometry and DTI could differentiate PSP-Richardson syndrome (PSP-RS) from PSP-parkinsonism, PSP-postural instability, and PD (area under curve >0.7). SWI did not differentiate among PSP subtypes or PD. ^18FFDG-PET distinguished PSP from PD.

MRI morphometry and DTI differentiated PSP-RS from the other common PSP subtypes and PD and may be tested as a radiological marker of PSP-RS in larger studies.